The invention relates to an anti-theft cap for fuel tanks of automobile vehicles, of the type comprising at least one device for placing the interior of the tank in communication with the exterior in the case of over-pressure or under-pressure within the tank, and a cylinder lock for locking and unlocking the cap.
In order to avoid the risks of explosion of the tank in the case of excess pressure or of implosion in the case of under-pressure, it is necessary to provide a communication between the interior of the tank and the open air.